DOVER - The local couple charged in connection with the murder of University of New Hampshire sophomore, Elizabeth "Lizzi" Marriott were actively looking for a "submissive" for sado-masochistic sex acts just before Marriott's death.

.According to documents unsealed Tuesday in the murder case against Seth Mazzaglia, 30, of Dover, he told police he and girlfriend Kathryn "Kat" McDonough were engaged in a consensual sex act with Marriott the night of her murder on Oct. 9...On Oct. 12, three days after Marriott was last heard from, police interviewed Mazzaglia, who allegedly recounted a variety of stories involving "BDSM" or bondage sadomasochism, gone too far...In a statement released by the Marriott family through attorney George Thompson following Mazzaglia's indictment in April, they said their daughter would not have consented to such an act...After initially lying to police, Mazzaglia later admitted that he had used a rope to strangle Marriott as part of a sex act while McDonough was in the room...He alleged that Marriott had what he described as a seizure during the act, but neither he nor McDonough rendered any aid or called for help, instead reaching out to a friend...Roberta Gerkin and Paul Hicock of Rochester allegedly arrived at the couple's Dover apartment on Oct. 9 after a frantic call from McDonough to find a young woman, naked except for underwear, with plastic bags tied around her head and face, according to the court records...Gerkin told police she removed the bags with a "box cutter" and that the woman had a "blue face" and appeared to be dead...According to court records, Mazzaglia told Hicock he "blacked out" during the act and said something along the lines of "this time I went too far."..Gerkin said Mazzaglia and McDonough were discussing "dumping the body" but could not be specific, according to court records...Mazzaglia later admitted to transporting Marriott's body in her car, and throwing it into the Piscataqua River from Peirce Island with McDonough's help. He later led police personally to the dump site, but Marriott's body has never been recovered...Mazzaglia and McDonough allegedly abandoned Marriott's car at a UNH parking lot and disposed of her clothes, their clothes and other items associated with the alleged crime in various Dumpsters between their Mill Road apartment, UNH and Portsmouth and shut off their cellphones to avoid having their locations "pinged."..Mazzaglia was charged with second-degree murder in October, and hundreds of pages of documents in his case remained under seal until Tuesday...On May 2, he waived arraignment on a slate of new charges out of Strafford County Superior Court including two counts of first-degree murder...The complaints allege that Mazzaglia strangled Marriott before, during or after committing or attempting to commit felonious sexual assault...In a recorded conversation in December, McDonough allegedly told Gerkin the death at first appeared to be accidental, and then turned "purposeful."..McDonough has been charged in Rockingham County Superior Court with hindering apprehension or prosecution and witness tampering...Search warrants were granted for a variety of electronic devices found in the couple's apartment including a videocamera, digital camera, and computers as well as for a variety of cellphone records...A search of McDonough's phone revealed a number of text messages between her and another friend discussing the BDSM lifestyle...It also revealed a number of text messages between her and Mazzaglia setting forth in "graphic detail" her role as a submissive and his role as dominant in BDSM sexual acts. Mazzaglia also discusses performing sexual acts on a friend of McDonough's while McDonough watches and/or having McDonough choose a friend that she would "offer" to Mazzaglia and that he would then do "anything" with the friend while McDonough watched, according to court records...Police discovered both Mazzaglia and McDonough had profiles on fetish sites, including www.fetlife.com, where Mazzaglia's profile details what he and McDonough were looking for in sexual submissives...The statement released by the Marriott family in April indicated, "The statements are a complete fabrication and are more indicative of Mr. Mazzaglia's twisted sense of reality and responsibility as opposed to Lizzi's character and the life she led for 19 years."..